<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      /*replace*/
      (function () {
        let str = 'aabbcc!';
        console.log(str.replace('a', 'd')); //dabbcc! //只替换一个
        //全部替换
        console.log(str.replace(/b/g, 'd')); //aaddcc!! //替换全部使用g
      })();
    </script>
  </body>
</html>
